Carboxylated cellulose nanocrystal cryogel monoliths: a multi-tool study of morphology and porosity of pure and magnetite nanoparticle-decorated CNC scaffolds

Tissue scaffolds are known to benefit from incorporation of nanoscale bio-additives like cellulose nanocrystals (CNC), which can affect porosity as an important tunable design parameter for bio-based scaffolds. In this paper, we probe how freeze-casting of carboxylated cellulose nanocrystals and CNC derivatized with magnetite nanoparticles yields macroscale cryogel scaffold monoliths. Cryogel topographical features and macropore morphologies depend on the conditions under which ice formation takes place, and on exposure to static magnetic fields. We examine porosity over several length scales with scanning electron microscopy (SEM) coupled with Local Thickness Euclidean distance image processing, small angle X-ray scattering (SAXS), and dynamic vapor sorption (DVS). SAXS data fitted with a mass fractal model and power law suggest that CNC particles aggregate to form well-defined compact walls in the range of 96.7–27.3 nm for all samples, while inclusion of Fe3O4 nanoparticles disrupts this compactness in the range of 27.3–4.8 nm. Analysis of DVS reveals that nanoparticles directly impact water uptake by the cryogel scaffolds and can reduce water sorption in mesopores with a radius of 5–6 nm

Versatile gold-silver-PB nanojujubes for multi-modal detection and photo-responsive elimination against bacteria

Bacterial infections have become a serious threat to global public health. Nanomaterials have shown promise in the development of bacterial biosensing and antibiotic-free antibacterial modalities, but single-component materials are often less functional and difficult to achieve dual bacterial detection and killing. Herein, we report a novel strategy based on the effective integration of multi-modal bacterial detection and elimination, by constructing the versatile gold-silver-Prussian blue nanojujubes (GSP NJs) via a facile template etching method. Such incorporation of multi-components involves the utilization of cores of gold nanobipyramids with strong surface-enhanced Raman scattering (SERS) activity, the shells of Prussian blue as both an efficient bio-silent SERS label and an active peroxidase-mimic, and functionalization of polyvinyl pyrrolidone and vancomycin, respectively endowing them with good colloidal dispersibility and specificity against S. aureus. The GSP NJs show operational convenience in the SERS detection and excellent peroxidase-like activity for the sensitive colorimetric detection. Meanwhile, they exhibit robust near-infrared photothermal/photodynamic effects, and the photo-promoted Ag+ ions release, ultimately achieving a high antibacterial efficiency over 99.9% in 5 min. The NJs can also effectively eliminate complex biofilms. The work provides new insights into the design of multifunctional core-shell nanostructures for the integrated bacterial detection and therapy

Lattice study on kaon pion scattering length in the I=3/2I=3/2 channel

Using the tadpole improved Wilson quark action on small, coarse and anisotropic lattices, $K\pi$ scattering length in the $I=3/2$ channel is calculated within quenched approximation. The results are extrapolated towards the chiral and physical kaon mass region. Finite volume and finite lattice spacing errors are also analyzed and a result in the infinite volume and continuum limit is obtained. Our result is compared with the results obtained using Roy equations, Chiral Perturbation Theory, dispersion relations and the experimental data.Comment: Latex file typeset with elsart.cls, 9 pages, 3 figure

MicroBundleCompute: Automated segmentation, tracking, and analysis of subdomain deformation in cardiac microbundles

Advancing human induced pluripotent stem cell derived cardiomyocyte (hiPSC-CM) technology will lead to significant progress ranging from disease modeling, to drug discovery, to regenerative tissue engineering. Yet, alongside these potential opportunities comes a critical challenge: attaining mature hiPSC-CM tissues. At present, there are multiple techniques to promote maturity of hiPSC-CMs including physical platforms and cell culture protocols. However, when it comes to making quantitative comparisons of functional behavior, there are limited options for reliably and reproducibly computing functional metrics that are suitable for direct cross-system comparison. In addition, the current standard functional metrics obtained from time-lapse images of cardiac microbundle contraction reported in the field (i.e., post forces, average tissue stress) do not take full advantage of the available information present in these data (i.e., full-field tissue displacements and strains). Thus, we present "MicroBundleCompute," a computational framework for automatic quantification of morphology-based mechanical metrics from movies of cardiac microbundles. Briefly, this computational framework offers tools for automatic tissue segmentation, tracking, and analysis of brightfield and phase contrast movies of beating cardiac microbundles. It is straightforward to implement, requires little to no parameter tuning, and runs quickly on a personal computer. In this paper, we describe the methods underlying this computational framework, show the results of our extensive validation studies, and demonstrate the utility of exploring heterogeneous tissue deformations and strains as functional metrics. With this manuscript, we disseminate "MicroBundleCompute" as an open-source computational tool with the aim of making automated quantitative analysis of beating cardiac microbundles more accessible to the community.Comment: 16 main pages, 7 main figures, Supplementary Information included as appendice

Integrated Optics Polarized Light and Evanescent Wave Surface-Enhanced Raman Scattering to detect ligand Interactions at nanoparticle surfaces

The orientation of sensing molecules on the surface of biosensors is crucial for effective interaction with target analytes, and Raman spectroscopy is a versatile and non-invasive technique used to study molecular configurations at the sub-nanoscale level. This study explores the sensing abilities of an integrated optics construct called an Optical Chemical Bench (OCB) for the detection of molecular orientation, ion binding, and nanoparticle binding. The OCB consists of plasmonic gold-silver nanoparticles bound to the surface of a multimode slab waveguide. This design offers controlled plasmonic excitation in both position and polarization, increasing the interfacial mean square electric field relative to the incident field, and allowing for polarization-dependent surface-enhanced Raman scattering (SERS) on a chip. The experiments gave insight into how the TE and TM polarization modes interact with adsorbates that are built up as hierarchical structures on the OCB, providing an inexpensive yet effective molecular probing technology at the interface

Morphology and porosity of pure and magnetite nanoparticles decorated porous cellulose nanocrystal cryogel monoliths

The investigation of porosity and porous materials have been of great interest to the medical field. Cellulose nanocrystals (CNC) are an attractive biocompatible natural material currently under development for use in tissue engineering. Herein, we probe the fabrication of carboxylated CNC-based cryogel scaffolds using the freeze-casting technique. We also employed a combination of characterization techniques to probe scaffold porosity, including scanning electron microscopy (SEM), small-angle X-ray scattering (SAXS), and dynamic vapor sorption (DVS). Our findings showed that macropore morphologies of the CNC-based cryogel scaffolds depend on the conditions under which water freezing takes place. The SAXS data fitted using the mass fractal model and power law suggest that the CNCs aggregated to form well-defined walls in the range of 96.7 nm – 27.3 nm for all samples, while the incorporation of nanoparticles disrupted this compactness in the range of 27.3 – 4.8 nm. The nanoparticles also showed a direct influence on water uptake of the cryogel scaffolds by reducing water sorption mesopores with a radius of 5 – 6 nm, as shown by the DVS technique

The obesogenity of restaurant food: Mapping the nutritional foodscape of Franklin County, Ohio using food review images

Geographical research on the community food environment emphasizes the spatial dimension of food access, where food quality and nutrition are overlooked. While the nutritional quality of food stores can be evaluated by audit tools, such as the Nutrition Environment Measurement Survey series, these tools cannot be readily applied on a large scale. To aid in the nutrition assessment of the community food environment, this article proposes an innovative image recognition approach that identifies the nutrition information of restaurant food by crowdsourcing food images and retrieving their nutrition information in a case study of Franklin County, Ohio. As these food images are derived from food review websites, they represent consumers\u27 actual dietary quality as a more direct, quantifiable measure of the community food environment. The derived nutrition information is applied for further analysis to characterize neighborhood obesogenity, referring to as factors in the built environments that facilitate the development of obesity. The proposed crowdsourcing-image recognition approach enriches the understanding of health inequities from a nutrition science perspective, which is beyond the tradition of food access in the spatial dimension only

Role of the 4,6-O-acetal in the regio- and stereoselective conversion of 2,3-di-O-sulfonyl-β-D-galactopyranosides to D-idopyranosides

The recently reported conversion of 2,3-di-O-sulfonyl-D-galactopyranosides to D-idopyranosides has provided an efficient route to obtaining orthogonally-protected idopyranoside building blocks with a β-1,2-cis glycosidic linkage. In an effort to expand the scope of this process and better understand the regio- and stereoselectivity observed in the key di-inversion step of the method, a small library of 4,6-O-acetal protected galactopyranosides has been synthesized and used as substrates in the process, together with a number of substrates that lack the acetal functionality. The results suggest that although the substituent at the acetal center does not contribute to the observed selectivity of the process, the acetal group is indeed required for efficient conversion by reducing the conformational flexibility of the substrate, resulting in enhanced reaction rates at both the O-transsulfonylation and epoxide ring-opening steps

Structure of Utp21 tandem WD domain provides insight into the organization of the UTPB complex involved in ribosome synthesis.

Assembly of the eukaryotic ribosome requires a large number of trans-acting proteins and small nucleolar RNAs that transiently associate with the precursor rRNA to facilitate its modification, processing and binding with ribosomal proteins. UTPB is a large evolutionarily conserved complex in the 90S small subunit processome that mediates early processing of 18S rRNA. UTPB consists of six proteins Utp1/Pwp1, Utp6, Utp12/Dip2, Utp13, Utp18 and Utp21 and has abundant WD domains. Here, we determined the crystal structure of the tandem WD domain of yeast Utp21 at 2.1 Å resolution, revealing two open-clamshell-shaped β-propellers. The bottom faces of both WD domains harbor several conserved patches that potentially function as molecular binding sites. We show that residues 100-190 of Utp18 bind to the tandem WD domain of Utp21. Structural mapping of previous crosslinking data shows that the WD domains of Utp18 and Utp1 are organized on two opposite sides of the Utp21 WD domains. This study reports the first structure of a UTPB component and provides insight into the structural organization of the UTPB complex